Search results
Results from the WOW.Com Content Network
An EMF meter is a scientific instrument for measuring electromagnetic fields (abbreviated as EMF). Most meters measure the electromagnetic radiation flux density (DC fields) or the change in an electromagnetic field over time (AC fields), essentially the same as a radio antenna, but with quite different detection characteristics.
Bipolar electrochemistry scheme. In electrochemistry, standard electrode potential, or , is a measure of the reducing power of any element or compound.The IUPAC "Gold Book" defines it as; "the value of the standard emf (electromotive force) of a cell in which molecular hydrogen under standard pressure is oxidized to solvated protons at the left-hand electrode".
The electromotive force generated by motion is often referred to as motional emf. When the change in flux linkage arises from a change in the magnetic field around the stationary conductor, the emf is dynamically induced. The electromotive force generated by a time-varying magnetic field is often referred to as transformer emf.
The emf of the cell at zero current is the maximum possible emf. It can be used to calculate the maximum possible electrical energy that could be obtained from a chemical reaction. This energy is referred to as electrical work and is expressed by the following equation:
The data below tabulates standard electrode potentials (E°), in volts relative to the standard hydrogen electrode (SHE), at: . Temperature 298.15 K (25.00 °C; 77.00 °F); ...
In fact, since the potentiometric measurement is a non-destructive measurement, assuming that the electrode is in equilibrium with the solution, we are measuring the solution's potential. Potentiometry usually uses indicator electrodes made selectively sensitive to the ion of interest, such as fluoride in fluoride selective electrodes , so that ...
The EMF of a concentration cell without transport is: E n t = R T F ln a 2 a 1 {\displaystyle E_{\mathrm {nt} }={\frac {RT}{F}}\ln {\frac {a_{2}}{a_{1}}}} where a 1 {\displaystyle a_{1}} and a 2 {\displaystyle a_{2}} are activities of HCl in the two solutions, R {\displaystyle R} is the universal gas constant , T {\displaystyle T} is the ...
Drawing from Edward Weston's US Patent 494827 depicting the standard cell. Weston cell Standard cell, extracted from case. Made in USSR. The Weston cell or Weston standard cell is a wet-chemical cell that produces a highly stable voltage suitable as a laboratory standard for calibration of voltmeters.